Serious worries about by 12 yo DS HELP

I don't have any good advice, just offering support. my year 7 ds is very hard work at the moment, very angry, everything is someone elses fault. he has had detentions for disruptive behaviour (obviously someone elses fault). hes always been challenging, but hasn't ever had a formal referral, though I have been tempted to seek one. I try and praise any small positive behaviour I see (sometimes an effort to find any!) and try and spend 1:1 time with him when he can be extremely pleasant company. but he is incredibly hard work, so I feel for you.

Bit of a backstory. Always been a dramatic personality from being very small. Always up or down, excited or unhappy.In yr 5 at school, school raised/supported my concerns and he was referred to CAHMS. Then referred to paediatrician for ADHD assessment.

A year this took. By the time school did their assessment he was in year 6, and his teacher (v strict), had put plenty controls in place and so his assessment came back as borderline for ADHD with oppositional defiance disorder.

We arranged some 1:1 counselling weekly for 10 weeks predominatly focussing on his impulsiveness and overreactions to certain situations.

Slight improvement.

Now in high school. His behaviour hasn't got worse, just different. Every issue is because a teacher hates him, someone provoked him, or he didn't mean it he was only joking. He really does not or cannot see the impact of his behaviour on others.

At home he swears, breaks his curfew for internet access, goes wandering telling me he is in one place but is somewhere else. Argues with everything. ANd has such a "victim" complex.

In fact my friend said to him last week "I never see you argue like this with your Dad (exh)".

He gets punished each time he does these kind of things, but doesn't seem to make any difference.

Anyway after a detention,subject report and a behaviour referral last week I am off to see his head of year later today.

What support should I be asking for - are any further assessments appropriate?

I can't punish him every day/week. our relationship is extremely strained at the moment.